How to find and qualify good Java developers Wallace Espindola Senior Java Developer & IT Architect

Main learning takeaways 1) Discover the Java market and technologies; 2) Step-by-step on how to find and qualify devs; 3) Where and how to search for devs.

● Dev market movement and numbers ● Java history and timeline ● What is (not) Java and related tech ● Frameworks front and back end ● Check and evaluate CVs ● Legacy x trending techs ● Junior x Mid x Senior ● Practical interview questions ● Tech profiles and possibilities ● Questions & answers Schedule

DISCLAIMER All of these slides are based on personal experiences over my 17 years’ career, developer’s interview experiences, personal opinions and some statistics.

About me ● Brazilian from Rio de Janeiro ● Electrical & SW Engineer, 17 years of career in IT ● Experiences in many industries: Government, Oil&Gas, Banking, Telecom, Defense, Education, BioTech. ● Expat in Belgium since early 2017 ● Profile: SW development & IT Architecture ● Stack: Back-end / Java / Web

High demand: So true nowadays! Why? Reason:

Some statistics: Java Top #3 language Source: www.githut.com

Tiobe: Java language compared Source: www.tiobe.com

Java: Among the top most active on GitHub Source: githut.com

Stack Overflow statistics Source: stackoverflow.com

Difficulties of the market Source: https://www.comptia.org/content/research/it-industry-trends-analysis-2021

Interesting Statistics and Insights https://insights.stackoverflow.com/survey/2021 https://www.tiobe.com/tiobe-index/ https://www.thoughtworks.com/radar https://githut.info/ https://madnight.github.io/githut/#/pull_requests/2021/4 https://dzone.com/

Java history

Huge number of technologies

A bit of terminology, too many J… J2SE / JSE (java standard edition) J2EE / JEE / Jakart EE (java web - enterprise edition) J2ME / JME (java mobile edition) JDBC (java database connectivity) JVM (java virtual machine) JDK / OpenJDK (Java Development Kit) JRE (java runtime environment) JAXB (java xml related) JSP (java server pages - old frontend) Javadoc (Java documentation) JPA (java persistence API) Javac (java compiler) Jar (java file containing classes) Java Beans (related to java objects) JMS (java message service) JUnit (java unit tests) JSF (java server faces - frontend) JaxRS (rest webservices specs) JMX (java mgmt extension) Non JAVA related: JavaScript (not java related - frontend) JQuery (not java related - frontend) JS (or .JS - frontend / javascript) Json (data type for webservices) Jboss (web server / container) Jasper (for reports) Joomla (CMS - content mgmt system) JRebel (fast compilation, no restart) Jetty (web server) Jersey (rest framework) Ajax (Asynch JavaScript And XML) JAVA related:

Most used/popular frameworks in Java Spring MVC Spring Boot Hibernate Maven Log4J / SLF4J JUnit Mockito / EasyMock Apache Kafka GWT (Google Web Toolkit) Grails Play Jersey Quarkus Micronaut Apache Spark Apache Camel Selenium Apache Hadoop Eclipse Vert.X Dropwizard EclipseLink Vaadin (a bit old) JSF (a bit old) Struts (old) JSP (old)

Java Roadmap 2022 Part 1/2

Java Roadmap 2022 Part 2/2

Most popular font-ends

Specialty Back-End Developer Front-End Developer Full-Stack Developer DevOps Developer Database Developer Mobile Developer Data Scientist Developer Big Data Developer

How to evaluate developer CVs? ↑ Number of experiences + ↑ Number of Trainings/Courses + Certifications + Years of Experience

Interviewing developers ● Avoid long process is DESIRED ● 01 Coding test is OK ● 01 RH interview is OK ● 01 Tech interview is OK ● Weeks for feedback is BAD ● No feedback at all is the WORST

Test online for developers https://codesubmit.io/ https://www.imocha.io/ https://codesignal.com/ https://www.codility.com/ https://www.testdome.com/ https://www.testgorilla.com/ https://www.hackerrank.com/ https://www.codingame.com/start https://devskiller.com/coding-tests/ https://coderbyte.com/organizations https://www.linkedin.com/skill-assessments/

Indicators: Is s/he updating/progressing?

Exposition and community engagement Participate in Java/Dev groups or communities Contribute to Open Source Projects Write technical articles to Blogs or LinkedIn Presence in Tech Meetups Presence in Tech Conferences Answers tech questions in Stack Overflow Trainings or courses given

Certifications: added value in the CV

Old / legacy tech / not sexy anymore Swing Desktop technologies Java FX Java ME JSP JSF Servlets Applets Jquery Struts EJB 2 Java under version 8 MyBatis / Ibatis JDBC pure XML PL-SQL Vaadin ZK OSS SVN / CVS DOM / SAX SOAP Webservices ANT Cobol Mainframe

Trending / sexy tech / calls dev attention Spring Boot Quarkus Microservices REST APIs Docker Vue.JS React.JS Event Driven Apps Reactive Programming Apache Kafka AWS / Azure / GCP / Cloud Java 11+ JavaScript / Typescript Kotlin JSON Kubernetes IntelliJ IDEA Functional Programming Node.JS NoSQL Elasticsearch (ELK) Jira/Confluence Git / Bitbucket / GitLab Websockets CQRS Android / IOS HTML5

Junior x Medior x Senior

A senior java developer profile must… Have lots of practical experience Know the theory base Know well OOP Know some design patterns Understand the frontend Know webservices Know SQL and Database Understand UML Understand unit/integration testing Be autonomous and take decisions Know how to analyze a problem Know how to estimate tasks Know how to make code review Know how to train/coordinate juniors Know how to prototype and present ideas/solutions Know how to write documentation Have architecture knowledge Have a good interaction in internal/external teams

3 questions to discover the level 1) What is the difference between interface and abstract class? (And tell me the advantages and disadvantages) 2) What is the difference between JPA x Hibernate x Spring Data? 3) What is the difference between Dependency injection x inversion of control x dependency inversion?

Practical experience questions 1) Please tell me about 3 design patterns you used and how 2) Please explain to me how and why you used polymorphism, overloading and overriding in a real system 3) We have an Invoice ID like 2022-xxxxx, where xxxxx is numeric and incremental, that must be unique in a system with a high number of simultaneous requests. How to solve that problem in the code, or using a framework, or using the database?

Diversity of profiles for IT Developers Engineers Mathematicians Physics Administration Economy Professors Geeks English French Dutch

Local people x expats Local is hard to find Remote Developer Employee x Freelancer VISA Sponsor Expat Status Regime India, South America, North Africa More years in career than in Europe After VISA/WorkPermit they stay 5 years Papers take up to 3 months

Questions

My contacts LinkedIn: https://www.linkedin.com/in/wallaceespindola/ GitHub: https://github.com/wallaceespindola E-mail: [email protected] Twitter: @wsespindola Thank you!!!